For Zebedi, rjh4242 & other W7 64 Calibre + Marvin + iPad users:
After importing ShellShock's "magic" 'DLL trio' to my 64bit Calibre v2.7 & again to v2.8 .....
successfully!! .....,
I also suddenly received the "Malformed database disk image" exception \ complaint.
After futzing around, I finally "cleared" out my Marvin iPad book database by simply uninstalling, shutting down & re-installing Marvin v2.8 on my iPad, updated to OS 8.1.
After re-connecting the iPad with an "empty Marvin" to W7 \ Calibre ....finally voila!!!!!
Reloaded Marvin's database by transferring batches of books from my Calibre library, 150 to no more than 250 at a time' until I successfully topped off at 2,214. Plus in the last two days, I've incrementally added more to a present total of 2,248.
So far Marvin's iPad DB remains UN-malformed AND All software & All Devices continue to Play Well Together!
Again, Lots of Appreciation due from W7 based users to ShellShock